As used herein, the phrase "industrial electrical connectors" is simply intended to distinguish the type of electrical connectors to which the present invention is directed, as opposed the typical household electrical connectors. The present invention is directed to connectors of the general class taught in U.S. Pat. Nos. 3,662,296 and 3,784,964. While their precise nature and configuration and the nature and configuration of the individual elements of such industrial connectors do not constitute a limitation of the present invention, in their simplest form, such connectors are provided as a cooperating male and female pair. The male connector comprises a male contact mounted within an insulative housing. The rearward end of the male contact is provided with means by which it may be connected to a cable or a bus bar. The female connector comprises a female contact mounted in insulative housing. The female contact is provided at its rearward end with means by which it may be connected to a cable or a bus bar. When the cooperating pair of connectors is in its mated or connected condition, the male contact is received within the female contact and a portion of the insulative housing of one of the connectors is received within a portion of the insulative housing of the other so that the male and female contacts are totally enclosed. In many industrial connectors, the insulative housings of a mated pair of connectors form a weather-proof seal about the contacts.
Prior art workers have devised a number of means by which such connectors may be locked together to prevent unintentional disconnection. One such locking means involves the provision of cam surfaces and cam surface engaging means in association with the male and female contacts so that when the male contact is inserted into the female contact and rotated relative thereto, the contacts will be in locked engagement. Such an arrangement is taught, for example, in U.S. Pat. No. 3,226,667. U.S. Pat. No. 3,755,772 teaches electrical connectors having exterior locking means. Some prior art connectors require tools to connect or disconnect them.
Many connector manufacturers use a threaded coupler to secure the connectors together. U.S. Pat. No. 3,029,407 is exemplary of such an arrangement. A threaded coupler is characterized by several disadvantages. The threads are easily damaged by handling or dropping on hard surfaces. Dirt frequently builds up in the threads. If the coupler becomes distorted from rough handling, the threads will not mate. Finally, it is time consuming to mate such couplers, expensive to machine the threads and the threads tend to seize and gall from dirt and corrosion.
The present invention provides a safety locking structure to prevent unintentional disconnection of a mating pair of male and female industrial electrical connectors utilizing the combination of a hollow shell structure, at least one U-shaped clevis pin and a locking pin groove on at least one of the male and female connectors. A clevis pin, per se, is not new as is evidenced by U.S. Pat. No. 3,397,012 wherein a U-shaped clevis pin is utilized as a retaining means to maintain a rotatable cutter bit for a mining machine or the like within its mounting means.
The unique combination of shell, at least one U-shaped clevis pin and a locking pin groove on at least one of the connectors, as taught herein, provides a locking system which eliminates the possibility of accidental disengagement of the electrical connectors which could otherwise cause disruption of service and electrical shock hazards. This locking system is easy and inexpensive to manufacture, simple in design and readily and quickly installable. No twisting of one electrical connector with respect to the other is required and the electrical connectors may be locked and unlocked without the use of tools or the like. The locking system can further be, itself, locked so that only authorized personnel can disengage the electrical connectors.
In the embodiments of the present invention, the clevis pin does not become inoperative due to dirt or corrosion. If the clevis pin becomes bent, it can be readily straightened and used. The locking means of the present invention enables the connectors to be quickly and easily locked or unlocked and the locking is positive.